Cold spray is used to inject microscopic powdered particles of metal or other solids into a supersonic jet of rapidly expanding gas and shooting them at a target surface. The solids ejecting from the spray exit so fast that when they come into contact with the target surface they stick to and coat the surface.
Technological advances in cold spray technology have rendered it useful in many different industries, such as the automotive and airplane manufacturing. For example, cold spray is used in the automotive industry to create a tough coating on car engine components made from lighter-weight composites, or to deposit layers of conductive metals onto substrates for use as heat-tolerant under-hood automobile electronics. However, still many problems are encountered in employing cold spray technology. For example, one problem in the cold spray process is powder residue build up in the cold spray nozzle during use. The rate of residue formation may be so high as to impact the throughput and cost-effectiveness of cold spraying as a substrate coating technique.